EP2316584A1 - Electrochemical anti-fouling system for structures wetted by sea water - Google Patents

Abstract

Electrochemical antifouling system (I), for combating the attachment of fouling organisms on seawater wetted building structures (02, 03), comprises a direct current circuit (23) for producing electrolysis in seawater, a grid structure electrode (05), at least a counter electrode (06) connected at the opposite poles of the grid structure electrode and an adjustable direct current source (07). Electrochemical antifouling system (I), for combating the attachment of fouling organisms on seawater wetted building structures (02, 03), comprises a direct current circuit (23) for producing electrolysis in seawater, a grid structure electrode (05), at least a counter electrode (06) connected at the opposite poles of the grid structure electrode and an adjustable direct current source (07), where (I) is characterized by: a form-stable formation of the grid structure electrode made of a single metal component of the lattice structure; a corrosion-resistant formation of the counter electrode; an arrangement of the grid structure electrode at such a distance range before the surface of the building structure to be protected in such a way that the surface lies in the area of influence of a pH-value-increase caused by the electrolysis of the seawater; an electrical insulation of the grid structure electrode against the surface of the building; and a device for alternative connection of the grid structure electrode either in a continuous operation mode with a circuit of the grid structure electrode as a cathode and with an adjustment of the direct current source, in which an accretion of soft brucite and a pH-value above the pH-value-tolerance limits of fouling organisms to be combated in the seawater occurs due to the production of current density at the grid structure electrode connected as cathode or in a temporary dismantling mode with a circuit of the grid structure electrode as the anode and with the adjustment of the direct current source, in which a reducing oxidation for completing dissolution of the grid structure electrode occurs due to the production of the current density at the grid electrode structure connected as anode. ACTIVITY : Antifouling. MECHANISM OF ACTION : None given.

Description

The invention relates to an electrochemical antifouling system for controlling the attachment of fouling organisms to seawater-wetted structures with a DC circuit for generating electrolysis in seawater with a lattice structure electrode, at least one spaced apart, opposite-polarity counter electrode and an adjustable DC power source.

Generally, the term "fouling" or "biofouling" (biological growth and growth) refers to the undesirable attachment of solids (marine organisms: bacteria, algae, clams, barnacles, etc.) at rigid interfaces. Anti-fouling measures are used to prevent fouling of buildings that are surrounded by marine or saline waters or liquid saline media ("seawater") or at least temporarily or permanently wetted. Offshore structures are usually constructed of steel or concrete, and are usually affected by fouling, especially in the tidal area. As a result, the surface for attacking the wave energy is increased, the surface of such structures permanently hidden and, if necessary. Attacked or corroded and locally increases the biological mass through the growth itself. Inspection work is made more difficult. In addition, falling down vegetation can lead to oxygen depletion at the bottom of the sea, especially in calming sea areas, and has a negative impact on marine animal communities. Furthermore, anti-fouling measures serve the protection of wooden parts in the water, such. As port pillars in marinas, before attaching and drilling organisms. Wooden components can be colonized by different organisms, which can lead to a complete coverage and thus to a restriction of the function of the components. In principle, fouling can thus destroy the surface of a building by adhering or seated organisms, so that more and more anti-fouling measures are taken. In addition to mechanical cleaning and special antifouling paints or coatings, electrochemical antifouling systems have also been developed, the major advantage of which is the non-toxicity.

STATE OF THE ART

Electrochemical antifouling systems are based on electrolysis in seawater. Under DC flow between anode and cathode arise dissociation products (cathode H ⁺ , anode OH ^- ), which lead to a local increase in the pH values at the interface between the electrode and seawater (cathode basic, anode acidic). In the U.S. 4,440,611 For example, a suitable current regime for generating electrolysis at the cathode is described in detail to prevent microbiological or calcareous fouling of seawater wetted conductive or semiconducting surfaces.

From the DE 41 09 198 C2 It is known to apply to the surface to be protected with a coating of a binder and macromolecules with free anionic or cationic groups on the molecule. By controlling the DC voltage, the dissociation products from the seawater deposit accordingly and lead to the formation of a specific pH at the surface. By protonation at the cathode, the pH can be raised to basic values of pH 9-10 when a voltage of 0.3 V / cm ² is applied. As antifouling protection is from the DE 41 09 197 C2 Known to switch the polarity of the DC voltage at random, so that the pH changes between acidic and basic. This repels organisms that can tolerate consistently high alkaline or acidic pH levels.

From the DE 698 02 979 T2 a similar antifouling system is known in which below a continuous conductive layer with a different resistance behavior nor a streaky structured layer or thin metal plates are applied in order to adjust the occurring current density depending on the vegetation targeted. From the JP 2004-278161 A is an antifouling system with the surface to be protected upstream electrode plates known. From the JP 2004-270164 A It is also known to store these electrode plates for mounting in rails.

Another consequence of electrolysis in seawater is the precipitation of minerals at the cathode (mineral accretion). This becomes comprehensive in the US 5,543,034 described. In particular, it is hard aragonite (polymorph of calcite, calcium carbonate CaCO ₃ , Mohs hardness 3.5 to 4.5, noticeable unidirectional splitting) and soft brucite (magnesium hydroxide Mg (OH) ₂ , Mohs hardness 2 to 2.5, light Cleavability in one direction). In particular, the deposition of hard aragonite can be used for the production of artificial reefs (Biorock technology), on which the growth of aquatic organisms is promoted. The observed during the deposition of aragonite pH increase of 0.1 compared to the equilibrium (average pH 8.2) leads to an increased growth of the organisms to be settled. Lime deposits also protect the cathode from corrosion.

Building on the Biorock technology, it is from the EAT reports (2001 NOMATEC Project, Topic "Electrochemical Accretion Technology" (EAT), introduction and progress reports 1st and 2nd project year, status 29.12.2004 , available on the Internet at the URL http://www.uni-due.de/nomatec/index_ de.html, Stand 29.09.2009) known to use a skeleton made of steel, preferably made of thin wire mesh fabric to produce an artificial reef as a cathodic matrix for the electrolytic lime deposition. The anode is a titanium mesh. It is recognized that the accretion of relatively soft brucite, which interferes with reef build-up, is indicative of high current densities in the cathode. By larger cathodic surfaces of brucite but can be counteracted.

Furthermore, from the DE 10 2004 039 593 B4 a process for the electrolytic extraction of brucite from seawater, in which the accretion of brucite is specifically supported by adding a magnesium salt solution. For the accretion of brucite, such a current density should be adjusted at the cathode that a pH of at least 9.7 (in normal seawater) is achieved. It has been found that a relatively low current density at the cathode results in the accretion product brucite in its crystalline form, while using a higher current density, brucite precipitates in the soft, soap-like form.

The closest prior art from which the present invention is based is disclosed in U.S.P. JP 07-268252 disclosed. Described is a generic antifouling system with a current-carrying, pliable mesh for a water inlet channel. The net is stretched as a safety net across the canal and along the canal walls. It forms the grid electrode and is connected as an anode. The cathode is rod-shaped and is arranged at a distance from the anode in the seawater. The cathode is not subject to any decomposition process and therefore consists of a non-corrosion resistant material, eg iron. However, in order to prevent erosion of the anode during the electrolysis, the mains cable is specially constructed. It consists of three cores, each made of nonconducting monofilaments around a conductive metal foil of titanium or a titanium-aluminum-clad material as the core. All three wires are embedded in a by the addition of platinum or titanium powder electrically conductive plastic jacket. To the To protect channel wall by anodic protection against fouling, the channel wall must be electrically conductive. The supply of the current into the network, especially in the metal foil in the core of the wires, via the electrically conductive channel wall. Removal of the network from the water inlet duct is only possible by manual dismantling, which requires deployment of on-site personnel.

TASK

The TASK for the present invention is seen in the further development of the antifouling system of the generic type so that the structure of the grid electrode is as simple as possible and undergoes no corrosion in normal operation. It should not be a mandatory requirement of an electrically conductive surface of the structure to be protected, nevertheless, a particularly effective fouling protection is to be achieved. Furthermore, a degradation of the lattice electrode without the use of local personnel should be possible. The solution according to the invention for this task can be found in the main claim, advantageous developments of the invention are shown in the subclaims and explained in more detail below in connection with the invention.

In the antifouling system according to the invention, the lattice structural electrode is dimensionally stable formed from a single metal component and thus extremely simple, robust and inexpensive in their construction. The grid structure electrode is self-supporting and remains in the selected form. It is arranged in such a distance region in front of the surface of the structure to be protected, that the surface is in the area of influence of a caused by the electrolysis pH increase of seawater. Anodic protection of the surface of the structure is not required. The counter electrode is made of a corrosion resistant material. Furthermore, the grid structure electrode is electrically insulated from the surface of the structure. This ensures that the current flows only through the grid structure electrode and not through the surface of the structure. Thus, the structure may be formed on its surface both electrically conductive and electrically non-conductive.

Furthermore, a device for alternative switching of the grid structure electrode is provided by these measures in the antifouling system according to the invention, which makes the handling of the system particularly versatile and simple. In principle, two different modes of use for the antifouling system according to the invention can be set with this switching device. On the one hand, a permanent operating mode with a circuit of the grid structure electrode can be selected as the cathode. By the cathode circuit, the grid electrode is protected from decomposition by electrolysis and thus from corrosion. There are no signs of wear, installation costs are only once. In this case, such an adjustment of the DC power source is selected that due to the current density generated at the grid electrode, an accretion of soft brucite and a pH above the pH tolerance limit of fouling organisms to be controlled in the seawater occur. In this operating position so a double antifouling protection is achieved. On the one hand by achieving a high pH in the seawater, which is above the tolerance limit of the fouling organisms to be defended. Here are z. As the pollard mussels (Pollicipes pollicipes) as Hartsubstratbesiedler to call that at a pH of about 8.9 rarely or no longer settle on surfaces. As a field size, the pH value has a far-reaching influence and thus also protects the surface of the structure lying behind the grid structure electrode from colonization. Fouling organisms are prevented from colonization. The application of direct current induces an electrolytic process, as a result of which the pH at the metal-water interface is greatly increased. The barrier thus constructed can not or only with difficulty penetrate organisms and their larvae when using adapted lattice structures. In this example is a Use of narrow mesh sizes with eg 0.4 cm to prefer, since this increases the pH increase per area even more.

On the other hand forms on the lattice electrode with localized influence a soft coating of brucite. Brucite has a perfect cleavage in one direction and is thus easily sheared off. Fouling organisms whose pH tolerance is exceptionally high or which can get used in exceptional cases to a constant increase in pH, are thus washed off shortly after the colonization of the lattice electrode together with the soft brucite by the seawater movement. At a pH of 9.7, brucite (Mohs hardness 2 to 2.5) is deposited on electrolysis. In particular, for producing high pH and brucite, a high current density in a range of 30 A / m ² with respect to the effective surface area of the lattice electrode and higher is set. A side effect here is the partly strong development and release of hydrogen, which occurs at high current densities due to the reduction of the cations at the lattice structure. This hydrogen evolution also has a positive effect on antifouling due to the incompatibility with organisms to be settled in the immediate vicinity.

The second mode of use in the invention is a temporary disassembly mode with a circuit of the grid electrode as the anode. By simply reversing the polarity of the current source, the grating structure electrode becomes the anode and thereby undergoes degradation during electrolysis. By the construction of a single metal component of the lattice structure complete degradation is possible quickly and easily. Thus, by simply reversing the DC power source, the grating structure electrode can be completely removed without requiring on-site personnel. This is a big advantage, especially for arrangements in inaccessible offshore areas. Removal may be, for example, in the case of - at least partially complete destruction, eg by destruction or excessive occupation of growth organisms of the lattice structural electrode - or at a distance of the building itself, be required. Then the grid electrode can be easily dissolved by reversing polarity and then - if the structure remains - be replaced by a new one. Possibly. existing electrical insulation of the grid structure electrode relative to the structure, such as insulators, remain on the building and can then be used again. If the metal component contains iron, no negative effects can be expected during the degradation or dissolution of the lattice structure (of any size), since iron is limited as an essential plant nutrient in the marine environment. A toxic load during degradation is avoided at all times. The amount of iron release can be controlled by the current density and the resulting surface potential of the connected as an anode grid electrode and thus dosed at any time.

In the antifouling system of the invention, the grid structure electrode is electrically isolated from the surface of the structure to be protected. On the one hand, this can be realized by the fact that already the surface of the structure is electrically non-conductive. These may be, for example, wooden structures - eg wooden harbor pillars - or concrete - eg foundation pillars of wind turbines. In the case of an electrically conductive surface of the structure-for example shut-off devices-insulators, for example made of plastic or ceramic, or an insulating mat, for example of plastic or mineral fiber, can be advantageously provided for the electrical insulation of the grid structure electrode with respect to an electrically conductive surface of the structure. In the case of a non-conductive surface, for example in buildings made of concrete or wood, the grid electrode may preferably be placed directly on the surface of the structure. Thus, not the entire structure is energized with its electrically conductive surface, but only the upstream lattice electrode, which positively by a low power consumption (low voltage) affects. The grid structure electrode in the invention is formed in a simple form of a single metal component. Advantageously, this can be a simple uninsulated steel or wire mesh, in particular even simple wire mesh can be used from a thin uninsulated steel wire. The counter electrode may be formed as a rod electrode and arranged in the seawater at a distance from the cathode. Advantageously, the counterelectrode can also be formed as a grid electrode. Likewise, it may be formed as a flat band electrode, which extends in front of the flat grid structure electrode. Also, the counter electrode is advantageously formed rigid and remains in a curved shape.

A particular advantage of the antifouling system according to the invention is its subsequent mounting on existing structures. Known systems generally do not have this advantage. A modular extension of the antifouling system according to the invention by connecting a plurality of grid structure electrodes and counter electrodes is also advantageously possible. This can be advantageous in the case of alteration or expansion of the structure to be protected or in the case of an initially only partial covering of the structure with the antifouling system. In principle, it is very advantageous for mountability if the lattice structure electrode and / or the counterelectrode are bendable. Due to the dimensional stability of the lattice structure electrode, this remains in any position, so it can be arranged self-supporting. Due to the flexibility, the grid electrode can also be optimally adapted to the shape of the structure to be protected. Even critical areas can be covered with the grid structure electrode. The same applies to the counter electrode, if this is also formed bendable. The bending is reversible, so that changes in shape during operation or even multiple applications - if no degradation of the grid electrode is provided by polarity reversal - are possible. Furthermore, especially when using simple wire mesh for the design of the grid electrode, its dimensional stability is not very pronounced. Then it may be advantageous if the grid structure electrode made of steel or Wireframe has a static folding. According to the nature of a lightweight construction, this measure achieves a substantial increase in the rigidity and thus the mechanical stability. As a result, the primary conductive grid electrode can be kept very thin and thus the entry of foreign material in the surrounding environment very low. Furthermore, the dimensionally stable, but bendable grid structure electrode can be adapted to curved surfaces of the structure to be protected. An adaptation of bendable, but dimensionally stable wire mesh to curved shapes, such as a breakwater, is easily possible. The same applies to the counter electrode. Furthermore, advantageously, a cylindrical configuration of the grid structure electrode and / or an annular formation of the counter electrode may be provided, wherein the counter electrode is arranged concentrically to the grid structure electrode. Thus, for example, both electrodes can advantageously be adapted to the round shape of a foundation pillar of a wind power plant. A concentric arrangement of grid structure electrode and counter electrode is possible: the grid structure electrode is placed around the foundation pillar, the counter electrode is then attached as a flat band ring with a slightly larger diameter over it. In the case of a foundation pier standing deep in the water, a plurality of counterelectrodes may be provided at a corresponding distance from one another above the height of the foundation pier.

In particular, in an arrangement of the antifouling system according to the invention on a foundation pillar of a wind turbine in an inaccessible offshore area is a self-sufficient power supply of the electrodes of particular advantage. Advantageously, therefore, a photovoltaic-powered DC power source can be used in the invention. The arrangement of photovoltaic elements in the overwater area of the wind turbine is easily possible. Often there are already such systems for powering other units. Likewise, however, is also a power supply from another regenerative source, for example via the transformer of Wind generator, easily possible and leads to the delivery of the controllable required direct current.

The components to be used in the anti-fouling system according to the invention are relatively inexpensive compared with the other antifouling solutions and represent with the low power consumption (low-voltage current) is a relatively inexpensive alternative. There are no chemicals or other harmful substances, especially toxins used. The antifouling system according to the invention is virtually wear-free, it does not have to be renewed regularly, as is the case with known antifouling paints. If necessary, the anti-fouling system can be easily removed on site with no staff costs.

Mechanical damage can be easily repaired. A local repair of, for example, short circuits is easily carried out by maintenance personnel. In conventional antifouling paints on an insulating layer on a metallic ship's hull such damage can only be cured by a complete renewal of the paint. Optionally, in a third mode, the temporary repair mode, partial damage to the grid structure electrode, which occurs, for example, as a result of the action of force or else by dismantling the grid electrode as the anode, can be repaired. The repair is carried out by deliberate addition of aragonite, which is electrically non-conductive and thus increases the electrical resistance in the circuit. Such a repair is therefore to be regarded as a temporary measure that protects the anti-fouling system from major damage until the arrival of maintenance personnel. After the repair, the aragonite can be easily removed by switching on the second mode for a short time. For temporary stabilization by aragonite still a current flow through the grid electrode is required so that only incipient damage can be repaired. Such damage can be detected for example by simple current measurements in the circuit. An increasing operating current is an indication of an increasing resistance and thus of incipient damage. In the repair mode, the grid structure electrode is switched as a cathode with such a setting of the DC power source that due to the generated current density at the grid electrode, an accretion of hard aragonite (Mohs hardness 3.5 ... 4.5) occurs. Mechanical weak points are thus temporarily stabilized by the addition of hard lime. The increased resistance by the non-conductive lime is compensated by dissolution of the aragonite in the second mode of use after the actual repair.

Finally, it should be noted that the effect of the antifouling system according to the invention described here according to the invention is very limited locally and therefore no risk for adjacent possibly sensitive materials such. B. on boats in port areas, or for people who are in the water means. Toxic components are also completely avoided in the invention. Further details of the antifouling system according to the invention can be found in the following specific description.

EMBODIMENTS

FIGUR 1

eine Ansicht auf das elektrochemische Antifoulingsystem bei einer Anordnung an einem Gründungspfeiler,

FIGUR 2

einen Querschnitt durch die Anordnung gemäß Figur 1 und

FIGUR 3

eine Ansicht auf einen Modulaufbau des elektrochemischen Antifoulingsystems an mehreren Pfeilern.

Embodiments of the electrochemical antifouling system according to the invention are explained in more detail below with reference to the schematic figures for further understanding of the invention. Showing:

FIGURE 1

a view of the electrochemical anti-fouling system in an arrangement on a foundation pier,

FIGURE 2

a cross section through the arrangement according to FIG. 1 and

FIG. 3

a view of a modular structure of the electrochemical anti-fouling system at several pillars.

The FIGURE 1 is a view showing the electrochemical antifouling system 01 according to the invention for the control of fouling organisms of adhering to a seewasserbenetzten Structure 02. These are in the selected embodiment to a foundation pillar 03, for example, a wind turbine, which is placed offshore in seawater 04 . The antifouling system 01 has a grid structure electrode 05 and two counterelectrodes 06 and an adjustable DC source 07 in a DC circuit 23. The grid structure electrode 05 is dimensionally stable and constructed of a single metal component. There are no material combinations, for example, from individual wires, conductive foil cores, electrically insulating fillers and electrically conductive sheaths used. In the exemplary embodiment, the grid structure electrode 05 consists of a simple uninsulated steel or wire mesh 08 made of a ferrous steel wire. The counter electrodes 06 are made of a corrosion-resistant material, for example of titanium or a titanium alloy.

The grid structure electrode 05 is bendable and adapted in the embodiment shown, the shape of the structure to be protected 02 . The grating structure electrode 05 encloses the foundation pillar 03 (diameter, for example, in a range of 1.5 m) from the waterline 09 downwards, for example over a height in a range of 3 m. This area is partially ventilated by the wave motion and therefore is particularly subject to fouling. The counterelectrodes 06 are likewise adapted to the shape of the foundation pillar 03 and designed as ring-shaped flat-band electrodes 10 concentrically enclosing the foundation pillar 03 . The counter electrode 06 may for example consist of a titanium-containing material and thus be corrosion resistant to the electrolysis. Further construction details of the antifouling system 01 according to the invention are the FIGURE 2 refer to.

In the FIGURE 1 Furthermore, a device 11 for alternative switching of the antifouling system 01 is shown in different modes of use. This device 11 is connected to the power source 07 and changes their current or polarity. The arrangement of the device 11 is shown only schematically. It can also be located further above on the structure 02 . Operation can be telemetric from far away via a transmitter. The current source 07 can be fed, for example, from a photovoltaic module using regenerative solar energy on the structure 02 .

The following modes of use can be selected in the antifouling system 01 according to the invention and achieved by adjusting the current:

I PERMANENT OPERATING MODE

In this mode, the grating structure electrode 05 is connected as the cathode (-) and the counter electrodes 06 as the anode ( + ). A high current J (unit mark A) is set so that a strong increase in the pH value occurs in the vicinity of the grid electrode 05 connected as cathode (-), which exceeds the pH tolerance limit of potential fouling organisms, so that they are repelled become. Furthermore, the current density J with respect to the surface of the grid electrode 05 connected as cathode (-) is selected to be so high that soft, shear-able brucite precipitates at the grid structure electrode 05 on which the organisms can not attach or slide together (parameter values) exemplary in the FIGURE 1 shown). In operation mode, therefore, a particularly effective double fouling protection is achieved.

II TEMPORARY DISMOUNTING MODE

In this mode, the grid electrode 05 is connected as the anode ( + ) and the counter electrodes 06 as the cathode (-). The current source 07 is reversed, the current flow reverses. In this mode, decomposition oxidation takes place at the grid structure electrode 05 connected as anode ( + ). At this time, the single metal component constituting the grid pattern electrode 05 is completely dissolved, so that the grid pattern electrode 05 is completely removed. Their disassembly is thus possible without staff on site. The speed of decomposition depends on the chosen magnitude of the current J and increases with it. With higher current J , in turn, a higher pH is achieved, which leads to a fouling protection, but which is no longer of importance in the disassembly of the lattice electrode 05 . This mode can only be selected temporarily.

At the counter electrodes 06 , the above-described operations take place in the disassembly mode. A decomposition of the counterelectrodes 06 does not take place due to the choice of material in any mode, so that the counterelectrodes 06 remain on the structure 02 after the disassembly of the structure electrode 05 . But as they usually do not have a large extent, their whereabouts is not disturbing. In the case of mounting a new grid electrode 05 , the counter electrodes 06 can be easily used again, so that their retention is even advantageous. The same applies to remaining insulation elements for the grid electrode 05

Optionally, in the antifouling system 01 according to the invention, a further mode of use may be provided:

III TEMPORARY REPAIR MODE

Damage to the grating structure electrode 05 , which has not led to an interruption of the circuit, can be compensated constructively in this mode. Advantage here is a temporary stabilization of the grid electrode 05 until the arrival of maintenance personnel who the Then repair damage, for example with replacement grille. The strength of the current J or the current density j is reduced so far in the repair mode III until hard aragonite precipitates and stabilizes again at the grid electrode 05 connected as the cathode (-). The pH drops, so that no more effective fouling protection is guaranteed. Therefore, this mode is only temporary to choose and is used to repair the cathode (-) connected grid electrode 05 without staff on site. Subsequently, by temporarily driving the use mode II deposited aragonite can be removed again.

The FIGURE 2 shows the antifouling system 01 in cross section through the structure 02 , the foundation pier 03 , in detail. In this case, the grating structure electrode 05 is arranged in such a distance region 12 in front of the surface 13 of the foundation pillar 03 , that the surface 13 is in the area of influence 14 caused by the electrolysis pH increase of the seawater 04 , so due to the strong pH increase under electrolysis, attachment of fouling organisms with a lower pH tolerance is prevented. Furthermore, the grid structure electrode 05 has an electrical insulation 24 with respect to the surface 13 of the foundation pier 03 . In the exemplary embodiment shown, the foundation pier 03 consists of an electrically conductive material, so that the grid structure electrode 05 is arranged on insulators 15 (compare section A in FIG FIGURE 2 ). Instead of the insulators 15 can also be an insulating mat 16 (see section B in FIGURE 2 ) are used, to which the grid electrode 05 is placed directly. In the case of an electrically insulating surface 25 , the grid structure electrode 05 can be placed directly on the surface 13 of the structure 02 (see section C in FIG FIGURE 2 ). The distance range 12 then approaches zero, so that the pH increase in the area of influence 14 in any case covers the surface 13 of the foundation pillar 03 and protects it from fouling. The counter electrodes 06 are ring-shaped and with a field-building Distance 17 to the grid electrode 05 arranged on further insulators 18 .

The FIG. 3 shows the arrangement of the antifouling system 01 according to the invention in a particularly exposed fouling area 19 on a plurality of buttresses 20 and buttresses 21, for example, a drilling platform. Evident is the modular structure of the antifouling system 01 with a plurality of grid structure electrodes 05 and counter electrodes 06 and their adaptation to the respective shape of the pillars 20 and buttresses 21st In the right part of the FIG. 3 a direct connection 22 of two grid structure electrodes 05 is shown. In the left part of the FIG. 3 a single arrangement is shown. All electrodes shown can be integrated in a common circuit or supplied in separate circuits.

Finally, exemplary values for the current density to be set in the antifouling system according to the invention are given, but they are not restrictive. use mode Current density j (A / m ² ) per effective grid area
(depending on the grid strengths used) I - operating mode 35 - 42
Note: at these current densities brucite deposition occurs. A pure pH increase takes place already at current densities in a range of 22 to 28 A / m ² . II - Dismantling mode 40 - 45 III - repair mode 30

LIST OF REFERENCE NUMBERS

01

electrochemical antifouling system

02

seawater wet structure

03

foundation piers

04

seawater

05

Lattice structure electrode

06

counter electrode

07

adjustable DC source

08

uninsulated wire mesh

09

waterline

10

ring electrode

11

Apparatus for alternative switching of 01

12

Distance range between 05 - 13

13

Surface of 02, 03

14

Area of influence Electrolysis with pH increase

15

insulator

16

Isoliermatte

17

Distance between 06 - 05

18

another insulator

19

Foulingbereich

20

buttress

21

buttress

22

Connection from 05 - 05

23

DC circuit

24

Electric Isolation

25

electrically insulating surface

Claims (10)

Electrochemical antifouling system (1) for controlling the attachment of fouling organisms to seawater-wetted structures (02, 03) with a DC circuit (23) for generating electrolysis in seawater (04) with a grid structure electrode (05), at least one opposing electrode ( 06) and an adjustable DC power source (07),
MARKED BY A dimensionally stable formation of at least the grid structure electrode (05) from a single metal component for the grid structure, A corrosion-resistant design of the counter electrode (06), An arrangement of the grid structure electrode (05) in such a distance region (12) in front of the surface (13) of the structure (02) to be protected, that the surface (13) in the area of influence (14) of an increase in pH caused by the electrolysis of lake water (04) lies, An electrical insulation (24) of the grid structure electrode (05) relative to the surface (13) of the structure (02, 03) and • A device (11) for alternative switching of the grid structure electrode (05) in one I. permanent mode of operation with a circuit of the grid electrode (05) as the cathode with such a setting of the DC power source (07), that due to the generated current density at the connected as a cathode grid electrode (05) an accreting of soft brucite and a pH above the pH tolerance limit of fouling organisms to be controlled in seawater (04) occur, or in one II. Temporary disassembly mode with a circuit of the grid structure electrode (05) as an anode with such a setting of the DC power source (07), that due to the current density generated at the as Anode switched grid electrode 05 takes place a reducing oxidation for complete dissolution of the grid electrode (05). Electrochemical antifouling system according to claim 1,
MARKED BY
Insulators (15) or an insulating mat (16) for electrical insulation (23) of the grid structure electrode (05) against an electrically conductive surface (13) of the structure (02). Electrochemical antifouling system according to claim 1,
MARKED BY
an embodiment of the grid structure electrode (05) made of an uninsulated steel or wire grid (08) as a metal component and / or the counter electrode (06) as a grid or ribbon electrode (10). Electrochemical antifouling system according to claim 1,
MARKED BY
a bendable design of grid structure electrode (05) and / or counter electrode (06). Electrochemical antifouling system according to claim 4,
MARKED BY
a pleating of at least the grid structure electrode (05) made of uninsulated steel or wire mesh (08). An electrochemical antifouling system according to claim 3 or 4
MARKED BY
a shape adaptation of the grid structure electrode (05) and / or the counter electrode (05) to curved surfaces (13) of the structure to be protected (02, 03). Electrochemical antifouling system according to Claim 6,
MARKED BY
a cylindrical formation of the grid structure electrode (05) and / or an annular formation of the counter electrode (06), wherein the counter electrode (06) is arranged concentrically to the grid structure electrode (05). Electrochemical antifouling system according to claim 1,
MARKED BY
a module-like expandability by connection (22) of a plurality of grid structure electrodes (05) and counter electrodes (06). Electrochemical antifouling system according to claim 1,
MARKED BY
a photovoltaic or otherwise regenerative DC source (07). Electrochemical antifouling system according to claim 1,
MARKED BY III. an optional temporary repair mode for damaged regions of the grid structure electrode (05) with a circuit of the grid electrode (05) as a cathode with such a setting of the DC power source (07), that due to the generated current density at the grid connected as a cathode grid electrode (05) an accretion of hard Aragonite occurs to protect the damaged areas.

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